--- title: Default Branch Migration linkTitle: Default Branch Migration description: | Instructions on how to migrate the default branch from master to main. weight: 99 type: docs aliases: [ "/rename" ] --- # Default Branch Migration This document outlines steps needed to migrate the default branch of your repo from `master` to `main`. Note: This document is currently a work in progress. If you have questions about the process, reach out to the GitHub Management Team on the [#github-management] channel on slack or open an issue in the [kubernetes/org] repo. ## Prerequisites - [ ] Create an issue in your repo to track the branch rename. You can paste this checklist in the issue body. - [ ] If you are not a root approver for the repo, assign a root approver for approval. - [ ] Once the issue has been approved, send a notice to your SIG's mailing list about the potential branch rename. ## Changes pre-rename Make the following changes _before_ renaming the branch the `master` branch. Note: There might be additional changes required that have not been covered in this checklist. Note: There might be additional information available in the umbrella issue via [kubernetes/org#2222]. ### Anytime These changes are **non-disruptive** and can be made anytime before renaming the branch. - [ ] If a presubmit or postsubmit prowjob triggers on the `master` branch (`branches` field of the prowjob), add the `main` branch to the list (see [kubernetes/test-infra#20665] for an example). - [ ] If the [`milestone_applier`] prow config references the `master` branch, add the `main` branch to the config (see [kubernetes/test-infra#20675] for an example). - [ ] If the [`branch_protection`] prow config references the `master` branch, add the `main` branch to the config. ### Just before rename These changes are **disruptive** and should be made just before renaming the branch. - [ ] For periodic prowjobs, or any prowjob that mentions the `master` branch in `base_ref`, update them to the `main` branch. Ensure that these changes happen in lock-step with the branch rename (jobs triggered in between landing these changes and renaming the branch will fail). - For bootstrap-based jobs, ensure the branch is explicitly specified, e.g. `kubernetes/foo=main`. [kubernetes/test-infra#20667] may eventually allow for non-disruptive changes. - For pod-utils based jobs, ensure the branch is explicitly specified, e.g. `base_ref: main`. [kubernetes/test-infra#20672] may eventually allow for non-disruptive changes. - [ ] If a prowjob mentions `master` in its name, rename the job to not include the branch name, e.g. `pull-repo-verify-master` -> `pull-repo-verify`. [`status-reconciler`] should automatically migrate PR status contexts to the new job name, and retrigger accordingly, but we have anecdotally found it sometimes misses changes. - NOTE: our infrastructure doesn't understand the concept of job renames, so from the perspective of e.g. https://testgrid.k8s.io the job will appear to have lost history and start from scratch. - [ ] If a prowjob calls scripts or code in your repo that explicitly reference `master`, update all references to use `main`, or auto-detect the remote branch - e.g. using git to auto-detect ```sh # for existing clones, update their view of the remote git fetch origin git remote set-head origin -a # for new clones, or those updated as above, this prints "main" post-rename echo $(git symbolic-ref refs/remotes/origin/HEAD) ``` - e.g. using github's api to auto-detect ```sh # gh is https://github.com/cli/cli, this will print "main" post-rename gh api /repos/kubernetes-sigs/slack-infra | jq -r .default_branch ``` - [ ] If the repo has netlify configured for it, ask a member of the GitHub Management Team to rename the `master` branch to `main` in the netlify site config. It can't be controlled through the netlify config in the repo. ### Approval - [ ] Once all non-disruptive tasks have been completed and disruptive tasks have been identified, assign the GitHub Management team ([@kubernetes/owners]) for approval. ## Rename the default branch - [ ] Rename the default branch from `master` to `main` using the GitHub UI by following the [official instructions]. ## Changes post-rename After the default branch has been renamed to `main`, make the following changes. Note: There might be additional changes required that have not been covered in this checklist. ### Prowjobs - [ ] If a prowjob still references the `master` branch in the `branches` field, remove the `master` branch (see [kubernetes/test-infra#20669] for an example). ### Prow config - [ ] If the [`milestone_applier`] prow config references the `master` branch, remove it from the config. - [ ] If the [`branch_protection`] prow config references the `master` branch, remove it from the config. ### Other - [ ] If any docs reference the `master` branch, update to `main` (URLs will be automatically redirected). - [ ] Ensure that CI and PR tests work fine. - If there are any outstanding PRs you can /approve to merge, do so to verify that presubmits and postsubmits work as expected - [ ] Trial the local development experience with a pre-rename clone. - ensure [Github instructions to rename your local branch] work - consider updating your fork's default remote branch name such that if you have git autocompletion enabled, typing `ma` will autocomplete to `main` - [ ] Send a notice about the branch rename to your SIG's mailing list. Include the link to the [GitHub instructions to rename your local branch]. [kubernetes/org]: https://github.com/kubernetes/org/issues [@kubernetes/owners]: https://github.com/orgs/kubernetes/teams/owners [#github-management]: https://kubernetes.slack.com/messages/github-management [kubernetes/test-infra#20665]: https://github.com/kubernetes/test-infra/pull/20665 [kubernetes/test-infra#20667]: https://github.com/kubernetes/test-infra/issues/20667 [kubernetes/test-infra#20669]: https://github.com/kubernetes/test-infra/pull/20669 [kubernetes/test-infra#20672]: https://github.com/kubernetes/test-infra/issues/20672 [kubernetes/test-infra#20675]: https://github.com/kubernetes/test-infra/pull/20675 [`status-reconciler`]: https://github.com/kubernetes/test-infra/tree/master/prow/cmd/status-reconciler [`branch_protection`]: https://github.com/kubernetes/test-infra/blob/ca6273046b355d38eade4c4bd435bd13fbb55043/config/prow/config.yaml#L131 [`milestone_applier`]: https://github.com/kubernetes/test-infra/blob/ca6273046b355d38eade4c4bd435bd13fbb55043/config/prow/plugins.yaml#L324 [official instructions]: https://github.com/github/renaming#renaming-existing-branches [GitHub instructions to rename your local branch]: https://docs.github.com/en/github/administering-a-repository/renaming-a-branch#updating-a-local-clone-after-a-branch-name-changes